Question

Which of the following is/are correct about Freundlich's adsorption isotherm for gases and solutions?

• A. $\frac{x}{m}=K{P}^{1/n}$
• B. $\frac{x}{m}=\frac{1+bP}{a}$
• C. $log\frac{x}{m}=logK+nlogP$
• D. $log\frac{x}{m}=logK+\frac{1}{n}logP$

Answer 1

Answer: (A), (D)

$log\frac{x}{m}=logK+\frac{1}{n}logP$

Freundlich adsorption gives the variation in the quantity of gas adsorbed by a unit mass of solid adsorbent with the change in pressure of the system for a given temperature. The expression for the Freundlich isotherm can be represented by the following equation:
$\frac{x}{m}=K{P}^{1/n}$

where n>1

Where x is the mass of the gas adsorbed, m is the mass of the adsorbent, P is the pressure and n is a constant which depends upon the nature of adsorbent and the gas at a given temperature. Taking the logarithm on both the sides of the equation, we get
$log\frac{x}{m}=logK+\frac{1}{n}logP$